AWACS - another chapter in a US classic, 'Who Makes Foreign Policy?'

While the world watches, President Reagan engages in a spectacular confrontation with Congress over who makes American foreign policy. At issue is the proposed sale of AWACS radar planes to Saudi Arabia.

Mr. Reagan hurried back from Cancun to take personal charge of lobbying the AWACS battle in the Senate, a battle which teeters in the balance with a vote scheduled Wednesday afternoon.

Mr. Reagan is the third president in 11 years to be challenged in a foreign affairs battle. And again, as in some past contests, an influential ethnic lobby could figure prominently in the outcome. Abroad, uneasiness is registered over which voice in Washington is the authentic one speaking on international affairs.

The Reagan administration proposed the sale to oil-producing Saudi Arabia on the grounds that it would help stabilize the Middle East. But Israel holds that the sale threatens its security. The House rejected it 301 to 111. It will go through, however, unless the Senate also vetoes it. The lobbying has become so intense that President Reagan told a news conference that it is ''not the business of other nations to make American foreign policy.'' This followed a visit of Israeli Prime Minister Menachem Begin.

The Constitution leaves uncertain who makes American foreign policy, the President or Congress. There have been explosions in the past, like the rejection of the League of Nations. Until Watergate and Vietnam, there was a lengthy period of congressional quiesence. The following five examples show Congress in a new aggressive phase.

1. Vietnam:

Congress took control of ending the unpopular war. In 1969, it banned introduction of US combat troops in Laos and Thailand. It passed the 1973 War Powers Resolution Act over presidential veto (requiring legislative sanction before use of troops). Eventually Congress wrote a rider into an appropriations bill telling the president to stop bombing Cambodia.

Congress insisted on writing a condition to a proposal by Richard Nixon in 1974 to give the Soviet Union most-favored-nation status in widening trade. The Soviets would only get such concession under the Jackson-Vanik amendment (Sen. Henry M. Jackson (D) of Washington and Rep. Charles A. Vanik (D) of Ohio) if it loosened up on emigration of Jews. The Soviets at first seemed to agree, then backed off when Senator Jackson specifically cited an emigration level of 60,000 a year, or 70 percent above the 1973 rate. Strong ethnic lobbying supported him, but Moscow ultimately balked. Emigration at one point dropped to 15,000. Jackson still held out for a Soviet commitment to ''free emigration.''

3. Cyprus (1974):

Congress overrode President Ford and penalized Turkey for invading Greek Cyprus with legislation cutting off further military aid. This time the ethnic lobby pushing the legislation was Greek. In return, Turkey suspended use of US bases within its borders. Mr. Ford twice vetoed the aid embargo. Foreign policy was the issue, he pleaded. The action, he argued, undermined the NATO alliance while America lost use of critical military bases. Congress relented only when President Carter took office in 1978, lifting the embargo.

4. Angola (1975):

President Ford called it ''a deep tragedy'' and ''an abdication of responsibility'' when Congress cut off Foreign Assistance Act funds in a Soviet-American clash over which rival sides to support in Angola, a former Portuguese colony. Russia used Cuban troops and South Africa invaded in October 1975. The US began giving covert aid to their own rival group. No, said Congress. The Senate voted 54 to 22 against the US aid, and the House 323 to 99. Mr. Ford said that because of Congress the Soviets had gained ''a stronghold in Africa,'' and Henry Kissinger declared, ''We had them defeated in Angola, and then we defeated ourselves.''

5. Salt II (1980):

While nuclear arms anxieties spread in Europe, President Carter ceased to push the Strategic Arms Limitation Treaty which he had signed after the Soviets invaded Afghanistan. Prior to that, the Senate showed no sign of giving the two-thirds treaty ratification required by the Constitution. Mr. Reagan calls the treaty ''fatally flawed.'' Technically it is still on the Senate's agenda.

The battle over the AWACS deal is a continuation of the resurgent congressional interest in foreign affairs beginning with Vietnam. Who controls foreign policy - the President or Congress? They both do. The struggle goes back to Madison and Hamilton. It has now involved Mr. Reagan's prestige so deeply that at times this issue seems more important than the sale itself.